Rohingya Muslim militants in Myanmar killed dozens of Hindu civilians during attacks last August, according to an investigation by Amnesty International.

The group called Arsa killed up to 99 Hindu civilians in one, or possibly two massacres, said the rights group. Arsa had denied involvement.

Arsa has released videos featuring its leader Ata Ullah (centre)

Amnesty says interviews it conducted with refugees in Bangladesh and in Rakhine state confirmed that mass killings carried out by the Arakan Rohingya Salvation Army (Arsa) took place in a cluster of villages in northern Maungdaw Township at the time of its attacks on police posts in late August.

The findings also show Arsa was responsible for violence against civilians, on a smaller scale, in other areas.

The killings came in the first days of an uprising against Burmese forces, who are also accused of atrocities.

The report details how Arsa members on 26 August attacked the Hindu village of Ah Nauk Kha Maung Seik. "In this brutal and senseless act, members of Arsa captured scores of Hindu women, men and children and terrorised them before slaughtering them outside their own villages," the report said.

According to the report, on 25 August last year, Arsa militants, aided by some local Rohingya, descended on the village of Ah Nauk Kha Maung Seik, in the northern Maungdaw township in Rakhine.

They rounded up all 69 Hindu men, women, and children, before executing 53 of them. . . killing 20 men, 10 women, and 23 children, 14 of whom were under the age of eight. Some who agreed to convert from Hinduism to Islam were freed.

The investigation suggests that a massacre of Hindu men, women, and children in Ye Bauk Kyar happened on the same day, bringing the estimated total number of dead to 99.

Raj Kumari, 18, who witnessed the attack, told Amnesty: “They slaughtered the men. We were told not to look at them. They had knives. They also had some spades and iron rods. We hid ourselves in the shrubs there and were able to see a little. My uncle, my father, my brother – they were all slaughtered.”

Another witness, Formila, 20, told Amnesty that the Arsa fighters had taken the men away to kill them, then “came back with blood on their swords, and blood on their hands. . . I saw men holding the heads and hair [of the women] and others were holding knives. And then they cut their throats.”

The Amnesty report, which has been verified through hundreds of witness accounts, is likely to be controversial because it backs up the assertion by Myanmar’s military and government that their campaign of violence carried out in Rakhine last year was in response to Arsa’s actions.

It has taken months for the full account to come out mainly because of lack of access to northern Rakhine state. The accounts by witnesses also reveal the level of fear that victims had about telling the truth, and that eight Hindu women who fled to refugee camps in Bangladesh were pressured by Arsa to make videos claiming the Myanmar military carried out the violence against them.

Laura Haigh, an Amnesty researcher who helped compile the report, said it had been “very difficult to get people to open up about Arsa, they are a very elusive group, and there is a fear among the community now in Bangladesh, with the informant killings last year, not to speak out and that there could be reprisals against those who do.”

Two wrongs do not make a right. But both historically and at the present time not all the Rohingya are quiet peaceloving followers of the religion of peace who want nothing more than to tend their goats in the quiet enjoyment of somebody elses village.